Journal of the Southeastern Association of Fish and Wildlife Agencies

The result of applying pre-flooding applications of simazine to warm-water hatchery ponds employed in the culture of largemouth bass, bluegill and channel catfish fingerlings is described. Rates of 10 and 15 pounds active simazine per acre appeared to reduce the incidence of algal growths such as Pithophora and Hydrodietyon and inhibited development of submerged rooted weeds. Effects generally persisted for one production period but were not noticeable in succeeding production cycles. Some indication was obtained that phytoplankton development was retarded but fish production was not appreciably lower in treated ponds that that in untreated ones. The development of zooplankton did not appear to be retarded by simazine applications to bass rearing ponds. Some advantages of pre-flooding treatment of warm-water hatchery ponds are discussed.

The results of 116 aquatic weed control experiments using 10 herbicides and their combination are discussed. Included are data for pre-emergent soil application during winter draw-down, pre-emergent total pond treatments and post-emergent applications. Pre-emergent soil application during winter drawdown was comprised of 31 experiments, testing varying concentrations of eight different soil sterilants for the control of rooted aquatic weeds. D.M.A. (disodium monomethylarsonate) showed promise as a pre-emergent control of southern watergrass (Hydrochloa carolinensis). Also, fenac (2,3,6 trichloro phenyl acetic acid) was effective in clearing fishing areas in ponds heavily infested with a variety of aquatic plants. Both liquid and granules were used at concentrations of 10 Ibs. and 20 Ibs, active ingredients per acre. Best results were obtained when even distribution of the herbicides was accomplished.

Several chemicals that have been used in fish culture for the control of filamentous algae are discussed. Their effects on fish and fishfood organisms in ponds are reviewed. Results obtained from applications of Karmex to 26 ponds are presented. Data show that Karmax was effective against several forms of filamentous algae at rates above one-half pound per surface acre. Rates up to three pounds per surface acre had no adverse effects on fish or fish-food organisms. Presented at the 18th Annual Meeting of the Southeastern Association of Game and Fish Commissioners, October 18-21, 1964, Clearwater, Florida.

The toxicity to bluegill sunfish (Lepomis macrochirus Rafinesque) of 15 new or reformulated herbicides is presented. Six phenoxy compounds assayed were within toxicity limits previously reported. The endothal derivatives tested were also within previous limits but did show promise as an aquatic herbicide. Substituted urea compounds checked did not demonstrate any differences from those previously reported. A pelletized formulation of sodium arsenite was very toxic but should be more convenient to apply.

The fluctuation of water level as a lake management practice in Louisiana is explained using three lakes as examples. These lakes vary from 1,000 to 2,600 acres and are scattered over the state. Anacoco Lake, a 2,600 acre impoundment in central Louisiana, was fluctuated primarily for aquatic vegetation control. The vegetation was reduced 90% over a period of three years. The effects on the fish population as shown in annual rotenone samples were an increase in the game fish of available size and a decrease in the intermediate size sunfish. Fishing success improved markedly. Bussey Lake, an impoundment of 2,200 acres in northeastern Louisiana, was extensively studied. Fluctuation data is presented showing that noxious vegetation was reduced over 95% in two years. The effects on both the fish population and fishing success were extremely favorable with harvest per acre up over 250%.

Four lakes representing widely different types but of generally comparable size are compared from the standpoint of sustained angler harvest. The range in size is from 1000 acres to 2200 acres, in age from 5 years to 30 years, and from an artificial impoundment to a cut off stream channel. All four lakes are dependent to a large extent on the metropolitan area of Monroe, Louisiana for their fishing public. The catch rate varied from 0.4 pounds per hour on Bayou DeBiard to 1.2 pounds per hour on Bussey Lake. The yield varied from a high of 215 pounds per acre on Bussey Lake to a low of 14 pounds per acre on Lafourche Lake. A general description of the four lakes is presented including comments as to the adequacy of the boat rental facilities and access points. The impact of these factors on the harvest is discussed. Heavy fishing pressure on the lakes under study did not cause a marked reduction in the catch per hour.

Food habits, feeding habits, and relative vulnerability of various prey species to predation by young longnose gar were studied as part of a general life history research project. Stomach analysis of yearling and older gar revealed a predominant fish diet with gizzard shad the most common species found. Seventy-six per cent of the stomachs of these gar were empty. Regurgitation is probably the major cause of the high percentage of empty stomachs of gar caught in gill nets. The stomachs of young-of-the-year longnose gar contained almost entirely fish, with various minnows the most common items. Feeding habits of the young gar are described. An experiment concerning the relative vulnerability of prey to predation revealed wide differences in the ability of various species to avoid capture by the gar.

Hybrids were produced by crossing the black, smallmouth, and bigmouth buffalo fishes. Growth-rate data for a two-year period are presented. The black x bigmouth individuals showed a pronounced acceleration of growth over that of the other hybrids and their parent spedes. Presented at the 18th Annual Meeting of the Southeastern Association of Game and Fish Commissioners, October 18-21, 1964, Clearwater, Florida.

During the 1964 striped bass spawning season, 383 female striped bass were treated with hormones at the Moncks Corner Striped Bass Hatchery and 337 (88%) were induced to ovulate as a result of the treatment. Three hundred and seventeen of the successful females were spawned in the hatchery for a yied of 322 million eggs and a hatch of 100 million fry. Chorionic gonadotropin was the most successful hormone used. Approximately 60 million fry were stocked in the Wateree Reservoir, a 13,710 acre impoundment, and early seining results indicate a significant survival.